What is Computer Software? Explain various Types of Software?

Computer Software

A computer  cannot  do anything  on its own.  It must  be instructed  to do a job  desired  by us. Hence,  it is necessary to  specify  a sequence  of instructions  a computer  must perform  to solve a problem.  Such a sequence  of instructions written  in a language  understood  by a computer  is called  a computer  program.  A program  controls  a computer processing  activity,  and the  computer  performs  precisely  what  the  program  wants  it to do.  When  a computer  is using a program  to perform  a task, we say, it is running  or executing  that program.

The  term  software   refers  to  a  set  of  computer   programs,  procedures.  and  associated   documents   (flowcharts, manuals,  etc.) describing  the programs,  and how they are to be used A software  package   is a group  of programs  that  solve  a specific  problem  or perform  a specific  type  of job. For example,  a word-processing package    may  contain  programs  for  text  editing,  text  formatting,   drawing  graphics, spelling  checking,   etc.  Hence,  a  multipurpose   computer   system,   like  a  personal   computer   in your  home,  has several  software  packages,  one each for every type of job  it can perform.

Types of Software

Software can be broadly classified in two categories:

1. System Software
2. Application Software

1. System Software

System software provides basic functionality to the computer. System   software   is a set of one  or  more  programs  designed  to  control  the  operation and  extend  the  processing capability of   a computer  system]  In general,  a computer’s   system  software  performs  one or more  of the following functions:

•  Supports development   of other application  software.
• Supports execution  of other application  software.
• Monitors effective use of various  hardware  resources  such as CPU, memory,  peripherals,  etc.
• Communicates with and controls  operation  of peripheral  devices  such as printer,  disk, tape, etc.

Hence,   system  software   makes  the  operation   of  a  computer   system  more  effective   and  efficient.

Some commonly known types of system software:

i. Operating System

ii. Programming Language Translators

iii.Communications Software

iv. Utility Program

i.Operating Systems

Operating system software takes care of effective and efficient utilization of all hardware and software components of  a computer system.   Different kinds of application software use specific hardware resources of a computer like CPU,I/O devices and memory, as needed by the application software. OS controls and coordinates the use of hardware among the different application software and the users. The key functions of OS are-

• It provides an environment in which users and application software can do work.
• It manages different resources of the computer like CPU time, memory space, file manager.
• It controls the execution of different programs to prevent occurrence of error.
• It provides a convenient interface to the user in the form of commands and graphical interface, which facilitates the use of computer.

Some available operating systems are Microsoft Disk System (MS-DOS), Windows 7, Windows XP, Linux, UNIX and Mac OS X Snow Leopard.

ii. Programming Language Translators

Programming   language  translators  transform  the  instructions prepared  by programmers   in language into a form that can be interpreted  and executed by a computer  system. There are three type of translator programs : Assembler, compiler and Interpreters.

iii. Communication Software

In a network environment, communication software enables transfer of data and programs from one computer system to another.

iv. Utility Programs

Utility program assist users in system maintenance tasks, such as disk formatting, data compression, data backup, and scanning a system for computer viruses. Some frequently used utility programs are:

a)  Disk Formatting Utility. To use anew disk (hard disk, floppy disk, or optical disk) on a computer system, we need to format it according to the requirements of the computer’s operating system. Disk formatting utility enables users to perform this task with great ease.

b) Data Compression Utility. This utility uses a compression algorithm to transform files into a fraction of their normal size, so that they occupy less storage space on disk, or can be transferred across a network in less time. It has an associated decompression algorithm used to convert a compressed file into its normal form and size when accessed by a user. It helps in significant saving of disk space _ it can effectively double the capacity of a disk.

c) Data Backup Utility. Data stored in a computer system can be damaged Or lost in several ways such as disk crash, virus, hardware malfunction, accidental deletion of files, or natural disasters like fire, earthquake, etc. Hence, we must always keep extra copies (called backup data) of important data. A backup utility enables creation of copy of data on some storage media, such as floppy disk, CD, pen drive, or magnetic tape. The storage media with backup data is often stored off-line away from computer system to prevent loss of critical data due to natural disasters. When some data stored on- line is damaged or lost, it can be restored from backup media. It is not necessary that backup media is always kept off-line. In today’s era of computer networks, some backup devices are kept on-line at a place away from main computer system and data backup on this device is done automatically by the computer system.

d) Antivirus Utility. A computer virus is a piece of code attached to a legitimate program that when executed, infects other programs in a system by replicating and attaching itself to them. In addition to this, replicating effect, a virus normally does some other damage to the system, such as corrupting/erasing files. Therefore, due to its spreading nature, a virus can cause severe damage to a system.

A typical virus works as follows. An intruder writes a new program that performs some interesting or useful function (such as some game or utility) and attaches a virus to it in such a way that when the program is executed, the, viral code is also executed. The intruder then sends this infected program by mail to other system users, or offers it free or for a nominal charge on floppy disks/CDs. Now, if anyone uses the infected program, its viral code is executed. While executing, the viral code selects an executable file on hard disk randomly and checks if it is already infected. Most viruses include a string of characters that acts as a marker showing that a program has been infected. If the selected file is already infected, the virus selects another executable file. When an uninfected program is found, the virus infects it by attaching a copy of itself to the end of that program and replacing the first instruction of the program with a jump to viral code. When execution of viral code finishes, it executes the previously bypassed instruction (the first instruction of original program) and then jumps to the second instruction so that the program now performs its intended function. Notice that a virus spreads because every time an infected program is executed, it tries to infect more programs. Also, notice that a virus does not infect an already infected file in order to prevent an object file from growing ever longer. This allows a virus to infect many programs without increasing disk space usage noticeably.

When a computer system suffers from virus infection, it has to be cured. Antivirus utilities are often used to cure a computer from virus infection. These utilities first identify the type of virus that has infected the computer by matching its marker against markers of well-known viruses. Once the type is known, original programs are restored from their infected versions by applying a detailed knowledge of the infection method used by the virus. For example, in viruses that modify jump instructions at the beginning of host program, recovering can be done simply by restoring the original jump to the start of the host program code. However, notice that these utilities can cure known viruses only. They cannot cure a newly encountered type of virus. A good antivirus utility can cure several hundred types of viruses normally and its power can be improved regularly by frequently updating it as new viruses are discovered. New generation anti-virus applications employ heuristic analyzer to monitor virus like activity and processing to tag or block memory containing seemingly dangerous instructions. This mechanism creates a working solution to tackle new viruses.

2. Application Software

Application  software  is a set of one or more  programs  designed  to solve a specific  problem,  or do a specific  task. For  example,   payroll  processing   software,   examination   results  processing   software,   railway/airline   reservation software,   computer   games  software   are  all  application   software.   Similarly,  a program  written  by a  scientist  to solve  a research  problem  is also application   software.  The programs  included  in an application   software  package are called  application  programs.  The programmers  who prepare’ application  software  are referred  to as application programmers. There  are  literally  millions  of application   software  available  for  a wide  range  of applications.   They  range  from simple  applications   such as word  processing,  inventory  management,   preparation  of tax returns,  banking,  hospital administration,     insurance,   publishing,     to   complex   scientific   and   engineering    applications    such as  weather forecasting,   space  shuttle  launching,  oil and  natural  gas exploration,   design  of complex  structures  like aircrafts, ships,  bridges,  sky-rise  buildings,  etc. With so many applications  available,  it is not possible  to categorize  them all and to cover them  here.

Some commonly  known  application  software  are:

i. Word-Processing Software

Word-processing    software  enables  us to  make  use  of a computer  for creating,  editing,  viewing,  formatting,   storing,  retrieving,  and  printing  documents   (written  material, such as letters, reports, books,    etc.)

ii. Spreadsheet Software

Spreadsheet  software  is a numeric-data-analysis    tool that allows  us to create a  kind of computerized   ledger.  A manual  ledger  is a book having  rows  and columns    that accountants use for keeping  a record  of financial  transactions   and for preparing  financial  statements.

iii. Database software

A  database   is  a  collection   of  related  data  stored  and  treated   as  a  unit  for information   retrieval  purposes.  A database  software   is a set of  programs  that  enable  us to  create  a database,   maintain   it (add,  delete,  and  update  its  records),   organize   its data  in desired  fashion  (for example,  sort  its records  alphabetically   name-wise),   and  selectively   retrieve  useful  information   from it. For example,  queries  such  as get the telephone   number  of the  person  named  Kashyap  Rana  from the  address  database,  or  get the  names  of all currently  enrolled   students  whose  birthdays  fall  today from the student  database  can be handled  easily.

iv. Graphics Software/Multimedia and Animation Software

Graphics   software  enables  us to  use  a computer   system  for  creating,  editing, viewing,  storing,  retrieving,   and printing  of designs,  drawings,  pictures,  graphs,  etc. For last few years, graphics, multimedia and animation software are becoming very popular for high quality presentation of business and other applications. CorelDraw, Adobe Photoshop and Auto CAD MAP are some of the commonly used graphic software. Multimedia, a latest computer technology displays information using a combination of full-motion video, text, graphics, animation and sound. A wide range of multimedia and animation software are available in the market. Macromedia Director, 3D Studio Max, Animator Pro and Animator Studio are some of the commonly used multimedia/animation software.

v. Personal Assistance   Software.     Personal  assistance  software  allows  us to use personal  computers  for creating, editing, viewing, storing, retrieving and printing of designs, drawings, pictures, graphs etc.

vi. Education    Software

Education   software  allows  a computer  to  be used  as a teaching  and  learning tool.   A  few  examples   of  such  software   include   those  used  for  teaching   mathematics,    grammar, language,  or any other subject.

vii. Entertainment Software

Entertainment   software  allows  a computer  to be used  as an entertainment tool. Computer  video  games  belong to this category  of software.